1. Field of Invention
This invention relates to a device for applying coating to fibers. In particular, this invention relates to a unique device for applying a controlled amount of a liquid coating to a moving fiber or fibers.
2. Prior Art
In the manufacturing of textile yarns, polymer filaments and other types of fibers, various chemical treatments are frequently applied to the fibers. (Fiber, as used throughout this specification and in the appended claims is intended to include all types of strands, threads, yarns, filaments, fibers, bundles of filaments, ribbons, bands, extruded wire and the like.)
At various stages in the processing of fibers, whether of synthetic or natural origin, they frequently are coated with a liquid coating. Except for dipping of the thread itself, which is often neither practical nor economical, the simplest method of coating application is by means of passing the fiber across some form of applicator onto which the liquid coating has been placed.
Liquid coatings are conventionally applied to threads using pads, rollers, sprays, belt applicators or other forms of contact applicators. All of these various contact-type applicators are positioned in receptacles of various shapes and dimensions. These receptacles contain the liquid coating to be applied to the fiber as well as the contact applicator means. For example, U.S. Pat. No. 1,621,303, Altemus discloses a yarn oiling device where yarn passes across a rotating roller wherein the roller is immersed in a receptacle for the oil.
U.S. Pat. No. 2,025,079, Whitehead discloses a similar apparatus for applying a liquid to a textile material wherein a disk having an edge is rotated in a receptacle containing the coating material. The thread runs across the disk perpendicular to the flat surface of the disk.
Various modifications to these conventional dip bath coating procedures have been designed for various coating applications relating to the coating or dying of fibers. For example, U.S. Pat. No. 3,492,840 Korsch discloses a double roller method for dyeing one surface of a fiber wherein one of the rollers is dipped in a dip bath while the second roller holds the fiber against the first roller.
U.S. Pat. No. 3,507,250 Dew, Jr. discloses a more complicated method for applying a coating to a fiber using the same dip bath roller procedure. In this patent a rotating disk is placed in a typical dip bath. As the disk rotates out of the dip bath a scrapper removes a portion of the coating from the disk and passes it down the surface of the scraper, preferably in troughs. At the edge of the scraper, the coating touches the surface of an applicator bar which may or may not rotate. Fibers pass over this applicator bar and are thus coated with the coating.
Certain improvements have been made in this rotating disk procedure for coating fibers. For example in U.S. Pat. No. 4,192,252, Paul and U.S. Pat. No. 4,548,840, States et. al. each of the rotating disks has an edge or a doctor blade for restricting the amount of coating which flows onto the surface of the rotating disk.
Other conventional apparatus for applying a liquid coating to the surface of a fiber or fibers using a rotating disk in a trough containing a liquid coating are disclosed in, for example, U.S. Pat. No. 4,121,901, Bourrain et. al., U.S. Pat. No. 3,993,805, Roberts, U.S. Pat. No. 3,811,834, Schwemmer et. al., U.S. Pat. No. 4,222,344, Parbhoo and U.S. Pat. No. 4,561,377, Youngkeit.
A refinement to this conventional rotating disk method for the application of a liquid coating to a fiber uses a belt-type applicator wherein the liquid is applied to the belt either by passing it through a trough or by pouring it onto the surface of the belt. See, for example, U.S. Pat. No. 2,873,718, Brautigam and U.S. Pat. No. 2,968,278, Wolfe.
Another method for applying a liquid coating to the surface of a fiber uses a double rotating disk wherein the first disk is placed within a trough and as it rotates it applies the liquid coating to a second disk. The second disk may have a doctor blade associated with it or other such devices for limiting the amount of liquid coating that is applied to the surface of the second disk. See, for example, U.S. Pat. No. 3,852,090, Leonard et. al. and U.S. Pat. No. 4,538,541, Zimmer.
A more sophisticated two cylinder delivering system for a liquid coating is disclosed in U.S. Pat. No. 4,517,916, Barch et. al. In the '916 patent a tubular hollow delivering system, (13) is supplied with a liquid coating for fibers. Since the coating is under pressure, it is extruded through a longitudinal opening (16) onto the surface of an applicator means (12), which is another cylindrical tube. As the applicator rotates, the liquid coating is extruded onto the surface of the applicator and then onto the surface of fibers which run over the surface of the applicator.
All of these systems for coating fibers generally contain an applicator rotating within a reservoir. After the applicator leaves the reservoir, the surface of the applicator contacts a moving fiber to coat it with a liquid coating. While many of these systems have been successful in the coating of fibers, they still have certain deficiencies. For example, the amount of the liquid coating to be applied to the fiber is not well controlled. This problem frequently results not only in too little liquid coating being applied to the fiber but at times too much being applied. In addition, some of the modern coating systems are quite complicated and expensive to manufacture. Thus, an easy, inexpensive method for applying a liquid coating to moving fiber is still needed in the industry.
Therefore it is an object of this invention to provide an easy, inexpensive device for the application of a liquid coating to a moving fiber.
It is another object of this invention to provide a device for the application of a liquid coating to a moving fiber wherein the applicator roller is not immersed in a reservoir.
It is a still further object of this invention to provide a device for applying a liquid coating to a moving fiber wherein the amount of the coating applied to the moving fiber can be carefully regulated.
These and other objects and features of the present invention will become apparent to those skilled in the art from a consideration of the following detailed description, drawings and claims. The description along with accompanying drawings provide a selective example of construction of the device to illustrate the invention.